Rare Pacific gray whale tracked on migration from Russia had previously been in North American waters

Photo analysis has confirmed that the highly endangered western Pacific gray whale dubbed Flex -- one of only 130 remaining -- was photographed in 2008 off Canada's Vancouver Island and was assumed to be part of the eastern gray whale population.

U.S and Russian researchers started tracking the male whale Oct. 4 when they tagged him with a satellite tracker off Sakhalin Island, Russia, as part of research into where the animals spend winters.

The whale left Russia's Kamchatka Peninsula on Jan. 3 and began swimming east. It swam halfway across the Bering Sea, turned southand swam between Aleutian Islands into the Gulf of Alaska. It continued southeast to shallow coastal waters off Washington and Oregon. Its last confirmed location was Feb. 4 off Siletz Bay, Ore., where researchers believe the satellite tag fell off. The whale had traveled 5,335 miles over 124 days.

The project stirred the interest of other whale researchers, said Dave Weller, a marine mammal ecologist for the National Oceanic and Atmospheric Administration's Southwest Fisheries Science Center in La Jolla.

"As we kind of watched that satellite track of Flex coming across the Pacific, we thought, 'We should put the photos of him in the hands of some eastern gray whale researchers to look for a match,'" he said. "Sure enough, they made one."

Weller is part of the Russia-U.S. Research Program on Western Gray Whales, a team of government and university scientists that have studied the animals since 1995.

The research team sent photos of Flex to Cascadia Research Collective, a scientific and education organization based in Olympia, Wash., for a comparison to its catalog of more than 1,000 eastern gray whales. The CRC catalog focuses on several hundred gray whales known as the Pacific Coast Feeding Group that feed during summer and fall in coastal waters between Northern California and the Gulf of Alaska rather than continuing north to the Bering, Chukchi or Beaufort seas.

A CRC catalog photo showed Flex in April 2008 in the Barkley Sound area off the west side of Vancouver Island. That summer, the whale was photographed back at the western gray whale feeding grounds off Russia's Sakhalin Island.

Analysts are now comparing the entire western gray whale catalog with CRC's catalog to look for additional matches. Weller said the process, done entirely by human eye, likely will take up to two months. Results will be presented at the International Whaling Commission's Scientific Committee meeting in June.

News of the match did not come as a complete surprise, Weller said. A NOAA colleague, geneticist Aimee Lang, studied samples of what were thought to be eastern gray whales collected between 1990 and 2006 off the North America west coast. Two samples that came from whales off California had genetic markers matching two western gray whales, leading Lang to suggest some "dispersal," or overlap, between the populations.

Eastern Pacific gray whales spend winters off Mexico breeding and calving and migrate north to feed during summer. With numbers estimated at 18,000, they are far more numerous than the western population.

Left unresolved is what Flex is doing so far from summer feeding grounds off Sahkalin Island.

"Good question," Weller said. "He's a 14-year-old male. As baleen whales and so many mammals go, those are the ones that actually tend to range the furthest into areas that may not necessarily represent the population as a whole but may represent a young male segment of the population."

Researchers still suspect that western Pacific gray whales may breed in the south China Sea. A female western gray whale first identified off Sakhalin as a calf in summer 2006 was found dead in a set net off the Pacific coast of Japan in January 2007. That's more than 932 miles south of the Sakhalin feeding area.

"With a sample size of one, it's really hard to go much beyond a single individual doing this," Weller said of Flex. "We need some more information."